WASHINGTON - More than two dozen world leaders will join President Obama in an extraordinary weekend of back-to-back summits to tackle Europe's mounting economic woes and solidify plans for winding down the decade-long war in Afghanistan.

The Group of Eight economic summit and the national security-focused NATO meeting will be infused with politics from every angle. For Obama, the summits are a unique election-year opportunity to show leadership on the world stage without having to leave the United States.

But with some new faces around the conference tables, Obama and the other leaders will be confronted by the stark reminder of the political turmoil from Asia to Europe that cost several of their old counterparts their jobs.

Since late 2011, public frustration with Europe's debt crisis has led to the ouster of leaders in Italy, Spain, Greece, and, most recently, France. Two other members of the G-8, Britain and Japan, have had leadership shake-ups since Obama took office.

Obama is fighting for his own job in a campaign expected to hinge on the economy. He has had the good fortune of being able to hold both summits this year in the United States, allowing him to tailor the meetings around his election-year messages of expanding the economy, creating jobs, and ending the war in Afghanistan.

Leaders from the world's eight leading industrialized nations arrive in the Washington area on Friday for meetings at Camp David, the presidential retreat in Maryland's Catoctin Mountains. Immediately after the G-8 summit, Obama and most of the other leaders will fly to Chicago on Saturday evening to join other heads of state from NATO.

Obama originally planned both meetings for Chicago, his hometown. But the White House abruptly scraped those plans in March, announcing with little explanation that the G-8 would shift to Camp David.

The White House said that location would lend itself to more intimate talks. It also will keep them far from the protests that usually flare on the summit fringes.

Diplomats said a major reason for the switch was to appear welcoming to Vladimir V. Putin, who recently reclaimed the presidency in Russia. Putin planned to skip NATO because of his staunch opposition to the alliance's planned missile-defense shield, and separating the two meetings was seen as a way to give Putin cover to slip away less awkwardly.

Ultimately those efforts were in vain. Putin told Obama last week that he was skipping the G-8 as well to stay in Russia and focus on forming his government. Russia's former president and current prime minister, Dmitry A. Medvedev, will attend the G-8 sessions.

The G-8 talks are expected to be dominated by the eurozone crisis.

Obama will largely play the role of facilitator.

"This is really for Europe to sort out," said Heather Conley, a Europe expert at the Center for Strategic and International Studies.

Obama will have a new ally in his calls for a growth agenda in Europe, new French President Francois Hollande. But administration officials say Obama plans to caution Hollande that Europe cannot abandon budget-cutting entirely.

Hollande will be in the spotlight as the weekend of summitry moves to Chicago, where NATO will firm up plans for how the alliance will finish its shift from a combat role in Afghanistan to an advisory role next year. Afghan President Hamid Karzai will be in Chicago, and NATO also has extended an invitation to Pakistan, which has yet to accept.